Stacking shape change powers

[holywhippet]

Say a druid uses wildshape, then someone else casts polymorph on them.

a) When the polymorph expires or the form runs out, does the character change back into their wildshape form or their original form?

b) What is the limit on the polymorph spell if the druid is wildshaped. The polymorph spell says to use CR or level if the target has no CR. While the form a druid changes into does have a CR, the wildshape rules don't specify you inherit that CR, just hit dice and HP.

[DarkKnightJin]

1) If there is time left on the Druid's Wildshape (which they should, unless the Polymorph hits bear the end of its initial duration), I'd let the Druid decide which form they return to if and when Polymorph runs out.

2) I'd stick with the Druid's level instead of the CR that the animal has, since that'd be a pretty big hit to Poly's usefulness. Plus, as you noted, the Wildshaped Druid doesn't take on the creature's CR.
They're just limited to what kind of creatures they can turn into based on CR.

[Crgaston]

Are druids even affected by polymorph?

“The spell has no effect on a shapechanger or a creature with 0 hit points.”

[sophontteks]

PCs don't have a CR

[DarkKnightJin]

Are druids even affected by polymorph?

“The spell has no effect on a shapechanger or a creature with 0 hit points.”

AFAIK, Druids don't get the 'Shapechanger' creature type added onto their 'statblock'.